Lubricant and method of lubrication



pasta June 4, 1940 n onwnnroanon Q g Theodore'G.;B.oehner, Malverne, andEmmett'S. Carmichael, Jackson-Heights, N. Y., assignors to Socony-Vacuum Oil Company, Incorporated.

. New York, N. Y., a corporation or New York No Drawing. Applicat ion December 11', 1 9 37,

s ri l-no. 179,256. '1 Claims. am -9 This invention is directed to a method oi lubrication and to lubricants for use in the high's'peed cold rolling of strip steeland in similar circumstances. The method of lubrication used in such 6 applications has an important bearing upon the,

efiiciency of the steel production process as a whole and few methods of lubrication and few lubricants now available are capable of withstanding the rigorous conditions imposed to give 10 a highly economical operation of the continuous high speed cold rolling strip steel process.

In this newly developed processor strip steel manufacture the speed of travel through the mills is relatively quite high and the rate of reduction.

is high in proportion to the speed. The product is used both for plating purposes such as in the production of tinned strip and a considerable amount is also used in the form of black sheet. The heat generated in this high speed reduction is dissipated by spraying the strip with water. Because of the large percentage of reduction at high speeds, the lubrication problem possesses the nature of a problem of extreme pressure lubrication. Because of the application of water it calls for lubricants persistent in the presence of water. Because the final use of the strip is in applications where the surface condition and/or appearance of the strip is very important, the lubricant must be capable of clean removal. As

an example of the conditions to be met, mills for the high speed cold rolling of strip may handle a sheet of a width of 26" to 28" at a rate of about 1400 feetper minute while reducing it in gauge from about 0.08" to about 0.008". The

strip material being rolled has been pickled prior to rolling. The heat arising from rolling is dissipated by the application of water sprays before and after rolling. Lubricant is applied to the strip material being rolled prior to each reduc- 0 tion in gauge, that is, the usual mill accomplishes the total reduction in gauge by passage through several sets of rolls, and the lubricant is applied prior to passage through each set of rolls, the first application of lubricant usually being immediately after the pickling operation while the sheet is being prepared for entry to the roll mill. The lubricant must discharge an extreme pressure function in that itmust be capable of. lubricating during reduction sufficiently to prevent seizure and marring of surfaces while at the same time it must not over lubricate to such a degree that there might be a tendency for the'rolls to slip upon the strip material rather than reduce it.

is its ability to give immediate reduction to final gauge, that is, with some oils not highly capable the rate of application of reduction to strip on commencing to pass through the mill may be're cuired to be so low that thestrip which passes through the mill in the first few seconds of operation is intolerablyover-size. With incapable lubricants this frequently requires the clipping I and rejection of 200 to'500 feet from the front end, 6

of each coil of strip which, of; course, represents an economic loss. The lubricant must also be able to withstand the action of the water sprays.

It must exhibit some capability for preferential wetting of heated metal in the presence of wa- 10 ter, otherwise the sprays would remove it. Of considerable importance the lubricant must be of such a nature that it can be readily removed from the finished strip by the usual process of elec-' trolytic washing in a slightly alkaline bath. This 15 capability of removal is important for strip to be of lubrication capable of permitting realization to thei'ullest extent of all of the production 30 economies inherent in this method of steel processing.

A further object is the provision of lubricants capable of permitting rolling with substantial reduction at high speeds without either seizure, '35

tearing, ormarring of the surface of the rolled material on the one hand, or slippage of the rolls on the other,

A further object is the provision of lubricants for these purposes capable of easy, thorough and 40 uniform application of lubricant film, capable of maintainingthat film in the presence of considerable quantities of water, capable of ready re- 7 moval after processing by the usual facilities available and possessed of relatively great free- '45 dom from producing stains upon the processed] material underthe conditions of processing.

This invention is based upon the discovery that these benefits may be obtained by applying to the i 1 steel strip in its progress'through the mill, cer- 5o tain novel lubricants which combine theproper- .ties outlined above, which novellubrioants are made by compounding together a lubricant oil base, palm oil; and a material of, the natureof an extreme pressure characterizing ingredient.

The principal ingredient in these lubricants in point oilvolurrie is the mineral oil lubricating base. Its natureis dependent upon the requirements of the particularmill or'operation to which it is tobe applied, It'mayrange from a mineral e0 A 12,203,501, mm,

oil of medium or low viscosity through oils of the nature of cylinder stocks of high viscosity and possessed of a somewhat waxy nature for applications where a material of higher viscosity is preferred, and it may preferably consist for most typical applications of a mineral oil fraction partaking very largely of the nature of petrolatum, or a mixture of mineral oil fractions of such nature that the final compounded lubricant has a viscosity of about 150 to about seconds Saybolt Universal at temperatures'of from about F. to about F. That is, for the usual application the mineral oil base is preferably the commercial product known as petrolatum, which is an amorphous wax substantially free from crystalline structure, and which may or may not contain mineral oil.' The palm oil fraction is the usual palm oil commercially supplied under the commercial designation of Niger palm oil. The extreme pressure characterizing bases may be of several of the-kinds usually 'used in the art for such purposes. For example, they may be any of the sulphurized fatty materials. A particularly useful form is that made by sulphurizing animal fatty materials such as, for example, sulphurized sperm oil containing about 15% of sulphur. Another form of extreme pressure characterizing base which, however, should be used only in rather minor quantities is the class known as chlorinated extreme pressure bases, particularly those made by chlorinating petroleum fractions as, for example, by chlorinating a petroleum fraction of medium viscosity until it contains about 30% of chlorine by weight. To exemplify several lubricants compounded of these ingredients and capable of use under the conditions outlined, the following examples are presented:

In the above example, the sulphurized sperm oil is one containing 15% of sulphur. The chlorinated mineral oil is an oil of medium viscosity chlorinated to contain 30% of chlorine. The paraffin oil is a light neutral oil of 100 seconds viscosity Saybolt Universal at 100 F. The petrolatum is a 122-130 F. melting point commercial grade petrolatum of Pennsylvania origin. The

compounded product has a melting point of about 119 F. and exhibits the physical characteristics of a petrolatum.

Example 2 A more fluid product may be made with the following formula:

Per cent by weight sulphurized sperm oil 5 Niger palm oil- 10 Cylinder stock- 85 In the above formula the cylinder stock is a commercial grade of cylinder stock produced as an over-head distillate from Coastal crude. The finished product is possessed of a flash of about 445 F., a pour test of about 10 F., a viscosity of 139 seconds Saybolt Universal at 210 F. and a colorwhich is dark green or almost black.

Example 3 For some applications a considerably more fluid material is indicated and under such circumstances the following formula may be found useful.

Per cent by weight sulphurized sperm oil 10 Chlorinated mineral oil 4 Niger palm oil 10 Sulphonic acid soaps .35

Paraflin oil 75.65

With the exception of the sulphonic acid soaps the ingredients used above are'as previously described. The addition of the sulphonic acid soaps is an optional feature. A small amount may be added to assist in removal of the material from the finished stock. The compounded lubricant is possessed of a pour of 15 F., a viscosity of seconds Saybolt Universal at 100 F. and a viscosity of 79 seconds at 210 F.

In the above formulae it must be understood that the composition indicated by Example 1, namely, that composition which has a consistency like cup grease and is based upon the use of a mineral oil fraction of the nature of petrolatum, is the preferred type of composition. When this composition is applied to the material passing through a mill for the high speed cold rolling of strip steel at a point prior to each major reduction in gauge as herein outlined, it will be found that the mill is enabled to perform at a uniformly high degree of efficiency securing complete reduction substantially from the instant of starting a strip through the mill, securing a smoothly finished sheet free of imperfections due to seizure and similar faults and producing a finished sheet substantially free from stains and imperfections due to the nature of the lubricant. It will also be observed that with the use of this lubricant the reduction in gauge is uniform and ancient with no tendency toward slippage of the rolls without performing useful work. Additionally,

the use of this lubricant, thus applied, will per-,

mit of attaining these results while securing a considerably reduced consumption of power for the production of a given amount of strip material. More fluid oils of this type as exemplified by Examples 2 and 3 do not permit of quite as good operation under the usual conditions as does the lubricant of Example 1. They do show however, that very considerable improvement over lubricants of the type formerly used which is possessed by all of the lubricants of the class herein discussed.

While. certain numerical examples and data have been given herein, it is to be understood that this invention is not limited thereby or thereto, but is subject only to such limitations as are expressed in the following claims.

We claim:

1. A lubricant composition comprising in excess of 50% of a heavy mineral oil fraction, not

more than about 20% of palm oil and not more:

than about 20% of substantially non-corrosive sulphur-containing extreme pressure lubricant bases. I I

2.-A lubricant composition comprising about 10% of palm oil, about 15% of extreme pressurematerial containing about 15% sulphur, about 4% of a chlorinated organic material containing about 30% of chlorine, about 15% of a low viscosity petroleum lubricant fraction and about 60% of petrolatum.

4. A lubricant composition consisting oi! Per cent by 1 v weight Sulphurized sperm oil 10 Chlorinated mineral oil 4 Niger palm oil 10 Mineral il 15 Petroiatum 61 5. A lubricant composition comprising about 10% palm oil, about 5% of sulphur-containing extreme pressure characterizing bases and a petroleum lubricant fraction 01' the nature of cylinder stock.

THEODORE G. ROEHNER. EMME'I'I S. CARMICHAEL. 

